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1 | /** @file\r |
2 | Routines supporting partition discovery and\r | |
3 | logical device reading\r | |
4 | \r | |
5 | Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>\r | |
6 | \r | |
eb6cb4ce | 7 | SPDX-License-Identifier: BSD-2-Clause-Patent\r |
6aac772c CC |
8 | \r |
9 | **/\r | |
10 | \r | |
11 | #include <IndustryStandard/Mbr.h>\r | |
12 | #include "FatLitePeim.h"\r | |
13 | \r | |
14 | /**\r | |
15 | Test to see if the Mbr buffer is a valid MBR\r | |
16 | \r | |
17 | @param[in] Mbr Parent Handle\r | |
18 | @param[in] LastLba Last Lba address on the device.\r | |
19 | \r | |
20 | @retval TRUE Mbr is a Valid MBR\r | |
21 | @retval FALSE Mbr is not a Valid MBR\r | |
22 | \r | |
23 | **/\r | |
24 | BOOLEAN\r | |
25 | PartitionValidMbr (\r | |
26 | IN MASTER_BOOT_RECORD *Mbr,\r | |
27 | IN EFI_PEI_LBA LastLba\r | |
28 | )\r | |
29 | {\r | |
30 | UINT32 StartingLBA;\r | |
31 | UINT32 EndingLBA;\r | |
32 | UINT32 NewEndingLBA;\r | |
33 | INTN Index1;\r | |
34 | INTN Index2;\r | |
35 | BOOLEAN MbrValid;\r | |
36 | \r | |
37 | if (Mbr->Signature != MBR_SIGNATURE) {\r | |
38 | return FALSE;\r | |
39 | }\r | |
40 | //\r | |
41 | // The BPB also has this signature, so it can not be used alone.\r | |
42 | //\r | |
43 | MbrValid = FALSE;\r | |
44 | for (Index1 = 0; Index1 < MAX_MBR_PARTITIONS; Index1++) {\r | |
45 | if (Mbr->Partition[Index1].OSIndicator == 0x00 || UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) == 0) {\r | |
46 | continue;\r | |
47 | }\r | |
48 | \r | |
49 | MbrValid = TRUE;\r | |
50 | StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);\r | |
51 | EndingLBA = StartingLBA + UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA) - 1;\r | |
52 | if (EndingLBA > LastLba) {\r | |
53 | //\r | |
54 | // Compatability Errata:\r | |
55 | // Some systems try to hide drive space with thier INT 13h driver\r | |
56 | // This does not hide space from the OS driver. This means the MBR\r | |
57 | // that gets created from DOS is smaller than the MBR created from\r | |
58 | // a real OS (NT & Win98). This leads to BlockIo->LastBlock being\r | |
59 | // wrong on some systems FDISKed by the OS.\r | |
60 | //\r | |
61 | // return FALSE Because no block devices on a system are implemented\r | |
62 | // with INT 13h\r | |
63 | //\r | |
64 | return FALSE;\r | |
65 | }\r | |
66 | \r | |
67 | for (Index2 = Index1 + 1; Index2 < MAX_MBR_PARTITIONS; Index2++) {\r | |
68 | if (Mbr->Partition[Index2].OSIndicator == 0x00 || UNPACK_INT32 (Mbr->Partition[Index2].SizeInLBA) == 0) {\r | |
69 | continue;\r | |
70 | }\r | |
71 | \r | |
72 | NewEndingLBA = UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) + UNPACK_UINT32 (Mbr->Partition[Index2].SizeInLBA) - 1;\r | |
73 | if (NewEndingLBA >= StartingLBA && UNPACK_UINT32 (Mbr->Partition[Index2].StartingLBA) <= EndingLBA) {\r | |
74 | //\r | |
75 | // This region overlaps with the Index1'th region\r | |
76 | //\r | |
77 | return FALSE;\r | |
78 | }\r | |
79 | }\r | |
80 | }\r | |
81 | //\r | |
82 | // Non of the regions overlapped so MBR is O.K.\r | |
83 | //\r | |
84 | return MbrValid;\r | |
85 | }\r | |
86 | \r | |
87 | /**\r | |
88 | This function finds Mbr partitions. Main algorithm\r | |
89 | is ported from DXE partition driver.\r | |
90 | \r | |
91 | @param[in] PrivateData The global memory map\r | |
92 | @param[in] ParentBlockDevNo The parent block device\r | |
93 | \r | |
94 | @retval TRUE New partitions are detected and logical block devices\r | |
95 | are added to block device array\r | |
96 | @retval FALSE No new partitions are added\r | |
97 | \r | |
98 | **/\r | |
99 | BOOLEAN\r | |
100 | FatFindMbrPartitions (\r | |
101 | IN PEI_FAT_PRIVATE_DATA *PrivateData,\r | |
102 | IN UINTN ParentBlockDevNo\r | |
103 | )\r | |
104 | {\r | |
105 | EFI_STATUS Status;\r | |
106 | MASTER_BOOT_RECORD *Mbr;\r | |
107 | UINTN Index;\r | |
108 | BOOLEAN Found;\r | |
109 | PEI_FAT_BLOCK_DEVICE *ParentBlockDev;\r | |
110 | PEI_FAT_BLOCK_DEVICE *BlockDev;\r | |
111 | \r | |
112 | if (ParentBlockDevNo > PEI_FAT_MAX_BLOCK_DEVICE - 1) {\r | |
113 | return FALSE;\r | |
114 | }\r | |
115 | \r | |
116 | ParentBlockDev = &(PrivateData->BlockDevice[ParentBlockDevNo]);\r | |
117 | \r | |
118 | if (ParentBlockDev->BlockSize > PEI_FAT_MAX_BLOCK_SIZE) {\r | |
119 | DEBUG((DEBUG_ERROR, "Device BlockSize %x exceeds FAT_MAX_BLOCK_SIZE\n", ParentBlockDev->BlockSize));\r | |
120 | return FALSE;\r | |
121 | }\r | |
122 | \r | |
123 | Found = FALSE;\r | |
124 | Mbr = (MASTER_BOOT_RECORD *) PrivateData->BlockData;\r | |
125 | \r | |
126 | Status = FatReadBlock (\r | |
127 | PrivateData,\r | |
128 | ParentBlockDevNo,\r | |
129 | 0,\r | |
130 | ParentBlockDev->BlockSize,\r | |
131 | Mbr\r | |
132 | );\r | |
133 | \r | |
134 | if (EFI_ERROR (Status) || !PartitionValidMbr (Mbr, ParentBlockDev->LastBlock)) {\r | |
135 | goto Done;\r | |
136 | }\r | |
137 | //\r | |
138 | // We have a valid mbr - add each partition\r | |
139 | //\r | |
140 | for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) {\r | |
141 | if (Mbr->Partition[Index].OSIndicator == 0x00 || UNPACK_INT32 (Mbr->Partition[Index].SizeInLBA) == 0) {\r | |
142 | //\r | |
143 | // Don't use null MBR entries\r | |
144 | //\r | |
145 | continue;\r | |
146 | }\r | |
147 | //\r | |
148 | // Register this partition\r | |
149 | //\r | |
150 | if (PrivateData->BlockDeviceCount < PEI_FAT_MAX_BLOCK_DEVICE) {\r | |
151 | \r | |
152 | Found = TRUE;\r | |
153 | \r | |
154 | BlockDev = &(PrivateData->BlockDevice[PrivateData->BlockDeviceCount]);\r | |
155 | \r | |
156 | BlockDev->BlockSize = MBR_SIZE;\r | |
157 | BlockDev->LastBlock = UNPACK_INT32 (Mbr->Partition[Index].SizeInLBA) - 1;\r | |
158 | BlockDev->IoAlign = ParentBlockDev->IoAlign;\r | |
159 | BlockDev->Logical = TRUE;\r | |
160 | BlockDev->PartitionChecked = FALSE;\r | |
161 | BlockDev->StartingPos = MultU64x32 (\r | |
162 | UNPACK_INT32 (Mbr->Partition[Index].StartingLBA),\r | |
163 | ParentBlockDev->BlockSize\r | |
164 | );\r | |
165 | BlockDev->ParentDevNo = ParentBlockDevNo;\r | |
166 | \r | |
167 | PrivateData->BlockDeviceCount++;\r | |
168 | }\r | |
169 | }\r | |
170 | \r | |
171 | Done:\r | |
172 | \r | |
173 | ParentBlockDev->PartitionChecked = TRUE;\r | |
174 | return Found;\r | |
175 | }\r |